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Old 05-11-2010, 04:01 PM   #1
lugoteehalt
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How get a webcam image large?


Just purchased a webcam and it worked immediatelly with kopete. This was in the configuration dialog, a small window showed me moving around in all my gloriousness. Now realise why those horror films show this sort of footage.

Thing is: how to make the image bigger, fill the screen? Is there a program? Don't say rtfm, I don't know enough to do that.
 
Old 05-11-2010, 04:32 PM   #2
TB0ne
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Quote:
Originally Posted by lugoteehalt View Post
Just purchased a webcam and it worked immediatelly with kopete. This was in the configuration dialog, a small window showed me moving around in all my gloriousness. Now realise why those horror films show this sort of footage.

Thing is: how to make the image bigger, fill the screen? Is there a program? Don't say rtfm, I don't know enough to do that.
Not to sound nasty, but if you don't know enough to read the manual, why would we think you'd know enough to do what we suggest here???

And with no information, there's no way we can answer your question. Some webcams only do small (640x480 or smaller) images, suitable only for low-end video conferencing. Some do higher res images at high frame rates. Since you don't say what brand/model you bought, we can't tell you what to do to make it bigger. What version/distro of Linux, too?
 
Old 05-11-2010, 09:06 PM   #3
lugoteehalt
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Quote:
Originally Posted by TB0ne View Post
Not to sound nasty, but if you don't know enough to read the manual, why would we think you'd know enough to do what we suggest here???

And with no information, there's no way we can answer your question. Some webcams only do small (640x480 or smaller) images, suitable only for low-end video conferencing. Some do higher res images at high frame rates. Since you don't say what brand/model you bought, we can't tell you what to do to make it bigger. What version/distro of Linux, too?
Well I'd just do what you said.

All I'm asking is since the thing obviously works what program can blow up the image bigger - surely it does not matter what the resolution is? Debian Lenny backport.

Code:
Bus 001 Device 004: ID 046d:0804 Logitech, Inc. Webcam C250
 
Old 05-11-2010, 10:21 PM   #4
TB0ne
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Quote:
Originally Posted by lugoteehalt View Post
Well I'd just do what you said.

All I'm asking is since the thing obviously works what program can blow up the image bigger - surely it does not matter what the resolution is? Debian Lenny backport.

Code:
Bus 001 Device 004: ID 046d:0804 Logitech, Inc. Webcam C250
Obviously, it *DOES* matter what resolution it is. If your camera can only capture 640x480, and you blow that up to 1280x1024, the image quality will be pitiful. Which is what you didn't like in your first post.

If you looked up the specs on your camera, 640x480 is the best it can do native. 800x600 software-enhanced, if you're running the Logitech software (which decreases frame rates, and only works on Windows/Mac). You can try to capture the image with Cheese, then put it into Gimp or any other photo editor and blow it up, but that's only good for stills.
 
Old 05-11-2010, 10:39 PM   #5
Shadow_7
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$ v4l-info

should list your camcorders abilities.

$ v4l-ctl

should help you setup which options you want to use. A lot of viewers mplayer, xawtv, tvtime, vlc, kaffiene, and others also let you select your input options if your webcam has more than one.

$ mplayer -fs .....

will play what it sees in full screen mode


I have a Sanyo FH1, this is what I use to use it as a webcam / capture device.

Code:
$ ffmpeg -f oss -ac 1 -ar 44100 -i /dev/dsp2 \
         -f video4linux2 -s 640x480 -pix_fmt yuvj422p -i /dev/video0 \
         -sameq -aspect 4:3 -f avi -vcodec mjpeg -acodec pcm_s16le \
         -r 30000/1001 -y - | \
         tee test.avi | \
         mplayer -cache 512 -ao null -vo xv -fs -
While not perfect, A/V is slightly out of sync. Frame rate is not consistent. The colorspace is actually better than it is as a camcorder. But it's an HD camcorder 1920x1080 @ 60 fps, so 640x480 @ 35fps is quite a step down. Although as a webcam, it's the best one I've ever owned.

Lots of -vfilter options in ffmpeg to upscale and perhaps enhance quality, but your starting data is your starting data and will likely never change. Webcams in general suck because their image sensors are so small and don't do well in low light at all, which is where you'll likely use them. One other option that you might consider is to lower the resolution of your X session. Artifical zoom. Cntrl+Alt+[+|-] from the number pad, if you have more than one resolution listed in your modes in your X configuration.

Basically RTFM because every device is different. Some have multiple drivers available and one has different abilities than another. And many means to an end.
 
Old 05-13-2010, 10:03 AM   #6
lugoteehalt
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Thanks both.

Code:
mplayer tv:// -tv device=/dev/v4l/by-id/usb-046d_0804_0B929D60-video-index0
Then f toggles fullscreen.
Code:
==========================================================================
Opening video decoder: [raw] RAW Uncompressed Video
VDec: vo config request - 640 x 480 (preferred colorspace: Packed YUY2)
VDec: using Packed YUY2 as output csp (no 0)
Movie-Aspect is undefined - no prescaling applied.
VO: [xv] 640x480 => 640x480 Packed YUY2  [vm]
XF86VM: Selected video mode 800x600 for image size 640x512.
Selected video codec: [rawyuy2] vfm: raw (RAW YUY2)
==========================================================================
Incidentally video for linux control is v4lctl, e.g.
Code:
v4lctl -c /dev/v4l/by-id/usb-046d_0804_0B929D60-video-index0 list
It would be nice if there was a systematic way to find the device name for things!

My point about RTFM is that it is pointless for everybody to constantly have to re-invent the wheel. It may be protestant work ethiky but it's inefficient.
 
Old 05-13-2010, 01:17 PM   #7
TB0ne
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Quote:
Originally Posted by lugoteehalt View Post
Thanks both.

My point about RTFM is that it is pointless for everybody to constantly have to re-invent the wheel. It may be protestant work ethiky but it's inefficient.
You're welcome, but I don't follow your logic.

If no-one reads the manual, how, exactly, would ANYONE know how to do ANYTHING? And, in a way, this whole SITE is a manual. Usually these days, cameras come up as /dev/video, or some such 'standard' device name, and it's linked to another name behind the scenes. Much like /dev/cdrom or /dev/dvd, is probably linked to /dev/sr0, /dev/sg1, etc., but you address it as /dev/cdrom to make life easy.
 
Old 05-13-2010, 02:36 PM   #8
Shadow_7
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Until someone writes an EASY button that actually works. RTFM is the only real way to MAKE it work. And a lot of times the manual is very minimal and/or out of date. So even that is of limited use.
 
Old 05-13-2010, 07:31 PM   #9
lugoteehalt
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Quote:
Originally Posted by TB0ne View Post
Usually these days, cameras come up as /dev/video, or some such 'standard' device name, and it's linked to another name behind the scenes. Much like /dev/cdrom or /dev/dvd, is probably linked to /dev/sr0, /dev/sg1, etc., but you address it as /dev/cdrom to make life easy.
Yes, for reference, the thing's device name is /dev/video1, /dev/video0 is the TV card. The device name above is probably the invariant one that symbolically links to /dev/video1, so that you always go to the device with it; but in this case /dev/video1 probably does not vary anyway.
 
  


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